Implementation of 2.4 GHz Digital Beamforming Doppler Radar for Monitoring Vital Signs

• Main Authors: Yu-Chi Huang, 黃昱齊
• Other Authors: Tzyy-Sheng Horng
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/b9z4hp

碩士 === 國立中山大學 === 電機工程學系研究所 === 107 === This thesis is devoted to human tracking and vital signs monitoring using a digital beamforming Doppler radar. Passive radar receives the external signal as the transmit signal. The radar of this work uses the continuous-wave signal from the signal generator to verify the experimental feasibility, and then adopts the Wi-Fi signal as the transmit signal to implement the passive radar architecture. The radar relies on baseband processing to detect the direction of the arrived signal. The subject locates at different positions, causing the reflected signal from the subject to reach each antenna with different phase differences. Using this phase difference, the direction of the subject can be estimated and his/her cardiopulmonary movement can be detected. After weighting the phase difference signals and then combining them, the radar can achieve human tracking and vital signs monitoring. However, the DC offset caused by the circuit and clutter often produces the error of direction. Therefore, this work uses two methods to remove the DC offset for reducing the error of direction. Finally, the experimental results are demonstrated and discussed to explore the limitations of this radar architecture and possible improvements for future applications.